Fluid in many producing oil and/or gas wells is elevated to the surface of the ground by the action of a pumping unit or a pumping apparatus installed in the lower portion of the well bore, such as an electrical submersible pump (ESP). The electric motor used in such systems typically generates considerable heat. To keep the motor from overheating, the motor is typically cooled by transferring heat to surrounding annular fluids. In many cases, the pumping unit is set in the well casing above perforations located in the well's producing zone. By placing the pumping unit above the perforations, the unit can make use of the fluid flowing passed the motor to cool the motor. Insufficient fluid velocity, however, will cause the motor to overheat and may lead to early motor failure.
To increase efficiency, it may be desirable to inject produced water into an injection formation and to deliver partially de-watered or oil-rich fluids to the surface. One ESP configuration that facilitates injecting water into the formation involves inverting the ESP. However, an inverted ESP configuration does not inherently allow for a flow of fluids passed the motor when the ESP is located above well perforations.
Therefore, it is desirable to facilitate cooling of an ESP motor in an inverted ESP configuration when the ESP is located above well perforations. It is further desirable to produce oil-rich fluids while re-injecting produced water into an injection zone.